briansquibb

Keep in mind that the 70-300 f/4-5.6 will not make use of the increased sensitivity f/2.8 center AF point. That means that the 70-300 f/4-5.6 will probably be a slight downgrade from a 70-200 f/2.8 mk2 AF-wise (and also from the prime, if its AF is as good as the 70-200 f/2.8's - I've not read much about it, it's way out of my reach). However, the 70-300 f/4-5.6 AF is still said to be quite good.

For the level of performance that you require from the AF, I would think that the only way to check if it is really up to YOUR needs, is to rent one and test it in your kind of situations. Users showing single easy-AF or even difficult-AF shots that ended up great on a forum like this, is no way to answer your question. You want the first image bang on with AF, preferably all the time, and I'm not sure if the lens will do that as well as the 70-200 f/2.8 II does.

With f/5.6 lenses, all the AF points will be horizontal-line sensitive only.With f/8 lenses, AF will be possible with the center AF point being horizontal-line sensitive only. AF will not work with the other AF points.

Keep in mind that the 70-300 f/4-5.6 will not make use of the increased sensitivity f/2.8 center AF point.

Thanks for the information about how valuable 2.8 really is - if anyone else could join in I'd be obliged because I nearly decided I'll get the 70-300/4-5.6 and save the 1000€ premium for the 70-200/2.8+extender combination.

Concerning af and light: good point, I nearly forgot about that. On the other hand, currently I'm shooting with an older 2.8 prime, and the 60D af is quite crappy anyway so I wonder how much worse it can get :-p

Does anyone have any first- or second-hand comparisons how much the af performance is lowered in real world applications when switching from 2.8 to something like f4-f5.6? Tele converters like the 2x lower the af speed, but I don't know if this is the reason.

Keep in mind that the 70-300 f/4-5.6 will not make use of the increased sensitivity f/2.8 center AF point.

Thanks for your information about how valuable 2.8 really is - if anyone else could join in I'd be obliged because I nearly decided I'll get the 70-300/4-5.6 and save the 1000€ premium for the 70-200/2.8+extender combination.

Concerning af and light: good point, I nearly forgot about that. On the other hand, currently I'm shooting with an older 2.8 prime, and the 60D af is quite crappy anyway so I wonder how much worse it can get :-p

Does anyone have any first- or second-hand comparisons how much the af performance is really lowered when switching from 2.8 to something like f4-f5.6? Tele converters like the 2x lower the af speed, but I don't know if this is the reason.

I can only relate to series 1 AF so that rules out help for you - but not for Harv who has the 1d4

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Tijn

Thanks for the information about how valuable 2.8 really is - if anyone else could join in I'd be obliged because I nearly decided I'll get the 70-300/4-5.6 and save the 1000€ premium for the 70-200/2.8+extender combination.

When using a 1.4x extender on the 70-200 f/2.8, it will effectively become 98-280 f/4 and so that combination will also not benefit from the f/2.8 focus points (but it will still benefit from all the f/4 crosstype points, which the 70-300 would not).Keep in mind though: the 70-300 AF is still "stellar", even with its relatively small apertures. When saying that the 70-300 is a downgrade AF wise, I'm primarily speaking in comparison to f/2.8 lenses (without extenders). Using an extender slows both aperture and AF, so the 70-200 would be much closer to the 70-300 in performance. But the 70-200 f/2.8 is still a more versatile lens, as it can be used without an extender in closer-distance situations with its increased f/2.8 focus ability, with the reduced DOF also being suitable for portraits and whatnot.

For me? I recently opened a long thread "Recommendation 70-200/2.8+2x vs 100-400 f/4-5.6L" and the conclusion for me was that for my outdoor activity, I want the 200-300 reach (i.e. less extender switching) and the lower weight - not to mention the much smaller price tag than 70-200/2.8+extender.

The only reason I am still thinking about the 70-200/2.8 because I might try to earn some $$$ in the future with photography. I am living in Berlin after all, so there's much competition but no end of good shooting occasions, too.

If people say I could start off with the 70-300 and my aps-c body, too, I'm fine - I can still sell the stuff and get full frame + 2.8 lenses for 5000€+ if it works out. On the other hand, If my starting combination would be so crappy that I couldn't do anything with it at all except amateur recreation shots, I might think again.

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briansquibb

But the 70-200 f/2.8 is still a more versatile lens, as it can be used without an extender in closer-distance situations with its increased f/2.8 focus ability, with the reduced DOF also being suitable for portraits and whatnot.

I can try to answer that for the 60D: Since the 70-200/2.8is2 is not the latest generation of Canon lenses - time moves fast - the af speed is lowered when using an extender. Other than the said 1D, on the 60D all 9 af points are cross up to f5.6 (except for a few legacy lenses, see link below). Thus, the faster af speed of the 70-300 should outweigh the difference to a slower f4 because the "high precision" center af is only available at f2.8 and better.

I use the 70-300L on the 1Ds3 for head and shoulders personal portraits where I find the clients prefer f/4 or f/5.6.

That's my personal experience, too - the reason is that a too bokehish background looks like the subject was standing in front of a green screen when shooting and then the background was replaced with a blur. Maybe this somehow seems to focus the eye too much on the portrait and the person's "shortcomings"? Or is it because you cannot get the tip of the nose into the dof at the same time as the ears with 2.8?

briansquibb

I find that for portraits they everythinng from the tip of the nose to behind the ear in focus. How much the bg is blurred is a function of the distance from the person to the bg.

I was shooting on Friday with the 400 f/2.8 + 2x II and didn't spot any slow down - was getting birds in flight without problem - so I suspect the slowdown is more apparent ih the lab than in the field

Brian, I checked this out with a friend. For the record, when shooting in AV priority or manual mode, and the lens is set wide open at f/4 on the 70mm setting, it shows in the viewfinder as increasing as the focal length is increased, ending up at f/5.6 for 300mm. When racked back, it starts to open up again, finally at f/4 on the 70mm setting.

As such, I'm guessing the available precision focus points will change as the focal length changes.

I'm now thinking the only way to find out if it will work well enough in a racing environment is to go with it and use it for a couple of races. If it doesn't work out, I can always sell it to one of you guys here.

Now I just have to wait a couple of months for the racing season to start.

Cardad

I am really happy with this lens for motorsports. I rented one last year for a race and it was so much faster focusing than my 70-300 non-L, I bought one. I am shooting a 7D, so I cannot compare my setup to yours. Also, I am just a hobbyist. I have pictures posted in Flickr if you are interested in seeing how some of mine came out.

Good pictures, I'm looking forward even more to next week when I'll get it myself :-) ... and to me it proves one of the few advantages of a smaller max. aperture lenses (apart from being cheaper and less heavy): You can just dial in 1/1000s in Tv mode like you did and shoot away w/o wondering if you end up with a too shallow depth of field of 2.8.

Good pictures, I'm looking forward even more to next week when I'll get it myself :-) ... and to me it proves one of the few advantages of a smaller max. aperture lenses (apart from being cheaper and less heavy): You can just dial in 1/1000s in Tv mode like you did and shoot away w/o wondering if you end up with a too shallow depth of field of 2.8.

.... on series 1 and 7d you can have it in M - dial in aperture and shutter speed and set iso to auto ....

I'm not new to Canon Rumors but have just recently joined the forums. I was hoping to find something a little more sane than the drivel over a DPReview.com. I'm beginning to wonder though. I read a couple of comments in this thread where the 70-300L IS was favorably compared to the 70-200L IS II. Only in someone's dreams do those two lenses compare in image quality for a full frame camera. The 70-300L is an EF lens but is positioned more as a step up for crop camera users. It is a great lens (optical quality-wise) for crop cameras and it is a good lens for FF; just not a great lens. It is ever so soft in the extreme corners on FF. In practice you wouldn't see it in most types of shots with shallow depth of field masking it but, if you're lens testing with something like a brick wall, it's visible in the shots...

From out of Canon's mouth:

"While it’s a great match for full-frame cameras, like the EOS 5D Mark II, this lens really comes into its own when used with an APS-C size sensor camera, like the EOS 60D or 7D, or a Rebel series digital SLR."

And, yes, I own both lenses. I personally wouldn't use the 70-300L for motorsports for a completely different reason. It is small enough that I'd want to handhold it but, if you do, the reversing of the zoom and focusing rings is a problem for me. I tend to cradle the camera/lens combination with my hand supporting the lens. With the two rings reversed, I tend to get on the focusing ring by mistake. I use the 100-400L instead...